Comparative study of the home range and habitat usage of red foxes and gray foxes in an urban setting: a preliminary report

George H. Rountree III

Abstract The shift of human population from rural to urban areas has lead to the rapid loss of rural and undeveloped land to urban development. Little is known about the effect these changes have had on . Eight foxes, 4 red foxes, and 4 gray foxes were tracked in an urban setting by radio telemetry. Home ranges were evaluated and a significant difference was found between gray foxes and red foxes in Newport News Park, Virginia. Female home ranges averaged 3.28 km2 and the male gray fox had a home range of 6.54 km2. Female home ranges averaged 2.12 km2 and male red fox home ranges averaged 3.04 km2. The male gray fox had the largest home range, 6.54 km2 and a male red fox had the smallest, 1.47 km2. Analysis of habitat usage indicated that gray foxes preferentially utilized open fields and mixed forest more than expected, and pine and hardwood forests less than expected. In contrast, red fox utilized fields and pine forests more than hardwood and mixed forests. Sound management of red foxes and gray foxes in urban settings must include an understanding of their home range and habitat needs in urban habitats.

INTRODUCTION Since 1900, the population of the United States and Japan (1 study) and Canada (1 study), but not in the Virginia has shifted from rural to urban settings United States (Harris 1981; Adkins 1991; White et al. (Serow and Spar 1972; Hall and Gaquin 1997) (Table 1996; Doncaster and Macdonald 1997). 1). Large tracts of forest and farmland have been lost The gray fox (Urocyon cinereoargenteus) is found from to urbanization and what remains in rural and urban southern Canada to northern Venezuela and Colom- areas are becoming fragmented. bia, excluding the central and northern Great Plains Newport News, Virginia is located on the lower and northern Rocky Mountains, Great Basin, Cascades peninsula of eastern Virginia and encompasses an area and Coast range (Fritzell and Haroldson 1982; Trapp of 177 km2. The population increased from 24,523 in and Hallberg 1975). Gray fox habitat is highly varied, 1900 to 171,439 people in 1990, and the city predicts including mixed pine-oak woodlands bordering the population will exceed 200,000 by the year 2000. pastures and fields, bottomland hardwoods associa- Since the 1960s, a continuous string of homes and tions along streams and creeks, citrus groves, railroad businesses has sprung up on a 20-mile corridor from rights-of-way, shrublands, brushy woodlands, and the old urban center of Newport News, leaving no rough rocky or broken terrain (Follmann 1973; Trapp concentration of open land. and Hallberg 1975; Nowak and Paradiso 1983; The red fox (Vulpes vulpes) rivals the gray wolf (Canis Sheldon 1992). A search of the literature found no lupus) for having the largest geographic distribution of reports addressing the effects of urbanization on the any contemporary living terrestrial mammal (Bueler gray fox. Harrison (1995), studying gray foxes in a 1980, Nowak 1991). Red foxes in North America are rural setting in New Mexico, found that home range found from the to the extreme southern United was inversely affected by human population densities. States (Bueler 1980). Habitats range from deep forest Reported home ranges of gray foxes in the United to arctic tundra, open prairie, and farmlands; the red States vary from 0.3 – 8.14 km2, with males having fox likes areas of highly diverse vegetation and avoids larger home ranges than females (Fuller 1978; Sawyer large homogenous tracts (Ables 1975). The red fox has and Fendley 1990; Harrison, 1995). Home ranges of been studied in urban and suburban sites in , red foxes in the United States have been reported to be

Author’s address: Christopher Newport University, 35 Ivy Farms Road, Newport News, VA 2360

238 Proceedings 4th International Urban Wildlife Symposium. Shaw et al., Eds. 2004 2.06 – 19.9 km2, in Iran approximately 50 km2, in posts. Traps were checked every morning. Foxes were Sweden from 4 – 12 km2, and in England from 0.21 removed from the trap, their fore and hind legs taped (urban) – 10.0 (rural) km2, with males having larger together, and their mouths taped shut. Ear tags and home ranges than females (Macdonald 1987; Major radio telemetry collars were applied, weights and and Sherburne 1987; Ingle 1990; Henry 1993, Reynolds measurements taken, and the foxes were then re- and Tapper 1995; Doncaster and Macdonald 1997). leased. The process was completed in approximately Sound management of red foxes and gray foxes in 10 minutes. Staff of Todd’s Lane Veterinary Hospital urban areas requires an understanding of their home were available to treat any injuries to trapped animals. ranges and habitat needs in these urban settings. With Eight of the 17 foxes trapped were fitted with radio the increasing conversion of wilderness and rural telemetry collars (2 red fox males and 2 red fox habitats to urban development, the need to under- females, 1 gray fox male and 3 gray females). L.L. stand the effects of this loss of habitat on red and gray Electronics radio-telemetry collars, Urbana Electronics foxes increases. This study may help predict problems CE-12 receivers, and Wildlife Materials antennas were other carnivores will face as they attempt to adapt to used to track the collared foxes. suburban or urban landscapes. The objectives of this study were to: Home Ranges Home range in this study is defined as the area used (1) estimate home range sizes of red foxes and gray on a daily basis. It may change with season and an foxes in an urban setting, animal’s age (Burt 1943). Home range differs from territory in that it is not defended. Home range, using (2) determine which habitats within this study site the minimum convex polygon method and excluding are most frequently used by gray foxes and red outliers (Burt 1943; Mohr 1947; Dixon and Chapman foxes. 1980; Samuel et al. 1985), was estimated using ArcView™ (Environmental Systems Research Insti- METHODS tute, Inc. 1996 GIS software). SigmaStat IIä for The study site is located in Newport News Park, on Windowsä (Jandel Scientific Software 1996) was used the southeastern peninsula of Virginia (approximate to evaluate home range and habitat usage for signifi- longitude 76°25´ and latitude 37°10´) and covers cance using the chi-square goodness – of – fit and t-test approximately 32 km2. The approximate boundaries of statistical techniques. the core study area are Ft. Eustis Boulevard on the north side, U. S. Highway-17 on the east side, Oriana Habitat Usage Road/ Old Denbigh Road on the south side and Movements and locations of foxes were tracked and Jefferson Boulevard on the west side with an approxi- plotted with aid of radio telemetry, GPS, GIS, and a mate area of 9.2 km2. Woodlands in the park are night vision scope. Every other day the foxes were dominated by loblolly pine (Pinus taeda), white oak located by telemetry and the habitat in which they (Quercus alba), and sweet gum (Liquidambar styraciflua). were found was described as pine forest, hardwood Numerous small creeks bisect the park. Harwoods forest, mixed forest or field. Fields were clear cut or Mill Reservoir and the regional airport are on the open areas with or without cover vegetation. Foxes southeast side of the study area. Single and multi- within 25m of human habitation, whether or not they family homes, shopping centers, and small businesses were actually seen or radio tracked within the bounds surround the rest of the study site. Elevation across the of a yard, apartment, condominium complex, were park varies little, ranging from 20m to 40m above considered to be near human habitation. A special note MSL. Soil found in this area is Slagle fine sandy loam. was made, if they were actually tracked or seen within Daily temperature average is 14°C, with lows in human habitation. January averaging -2°C and highs in July averaging 25°C. There is an average of 206 frost-free days and RESULTS 119cm of precipitation yearly. Using recent aerial Seventeen foxes were trapped and radiocollared; 8 photographs and ground truthing, the author classi- foxes were included in this study. Four red foxes (2 fied and determined the proportion of the core study males and 2 females) and 4 gray foxes (1 male and 3 areas in pine, hardwood or mixed forests or fields. females) were tracked for a minimum of 2 months, 1 female red fox was tracked for 12 months, the mean Capturing and Handling was 5.13 ± 3.85 months for this study. The day was Foxes were trapped using No. 1 ½ Victor coilspring divided into four 6hr blocks, and each fox’s location padded leghold traps to minimize the chance of injury. was recorded least once every other day during 1 of Traps were baited with commercial fox lure and urine. four 6hr blocks. Trap sets were along roadways, game trails, and scent

Proceedings 4th International Urban Wildlife Symposium. Shaw et al., Eds. 2004 239 Home Range male to 80.0% telemetry fixes for a gray female). As a A significant difference existed between the mean group, foxes were found more frequently than home ranges of gray foxes (4.09 ± 1.64) and red foxes expected in fields (observed = 41.5%; expected = (2.58 ± 1.39)(Table 1.) (t(6) = 6.04, p<.01). Mean home 34% of telemetry fixes) and less frequently than range for red foxes and gray foxes combined was expected in hardwood forests (observed = 8%; 3.34 ± 1.62 km2 with a range of 1.47 – 6.54 km2 (Table expected = 14% of telemetry fixes) (Figure 1). 2). For the red fox males, mean home range was larger (3.04 ± 2.21 km2) than for females (F) (2.12 ± DISCUSSION 2 0.11 km ). Only 1 male gray fox home range (6.54 Home Range km2) was included in this study, but it was larger 2 The size of red fox home ranges in Newport News than the mean for the 3 females (3.28 ± 0.23 km ). Park fell within published ranges for red foxes in the Home range size varied from 1.47 km2 for 1 male 2 United States (Nowak and Paradiso, 1983; Major and red fox to 6.54 km for the male gray fox (Table 2.). Sherburne 1987; Ingle 1990). The home ranges of the The smallest and largest red fox home range was for red foxes in this study are larger than home ranges the 2 males, the smallest was 1.47 km 2 and the 2 reported for urban red foxes in England (Macdonald largest was 4.6 km . The smallest gray fox home 1987; White et al. 1996; Doncaster and Macdonald range was 3.01 km2 and the lone gray male had the 2 1997). largest home range, 6.54km (Table 2). Home range sizes obtained for the gray foxes in Core is defined here as an area equal to or less 2 this study were also within the reported ranges for than 0.5 km that contained at least 25% of the gray foxes in the United States (Fuller 1978; Sawyer telemetry fixes of a fox. Four of the foxes had and Fendley 1990; Harrison 1995). There are no definite core areas (Table 2.). Two of the 3 female 2 studies of gray foxes in an urban setting, but gray foxes had core areas (0.41 km for 46% of the 2 2 Harrison (1995) gives a home range of 7.0 km in his total telemetry fixes and 0.44 km for 83% of the study of gray foxes in a developed rural setting. The telemetry fixes). One red fox female had 2 core areas 2 2 home ranges of urban gray foxes in this study were (0.34 km for 48% of the telemetry fixes and 0.20 km smaller than the home range of the gray foxes in for 30% of the telemetry fixes). The smallest core Harrison’s study. area (0.15 km2) was for one of the male red foxes. These core areas did not appear to change during Habitat Usage breeding and whelping seasons. Linzey (1998) states, that the gray fox is more of a woodland species than the red fox. In contrast to Habitat Usage expectation, this study found gray foxes on the Foxes used some habitat types more than others 2 edges, even outside, of the park boundaries and (Figure 6) (x =18.0, df=3, p<0.01). Both gray foxes close to or among human habitation (Harrison 1995). and red foxes were found more than expected in One female was found twice in the middle of a fields (observed = 50.0% and 36.6%, expected = 34% condominium complex. A second female spent 80% of telemetry fixes) (Figure 1). Gray foxes were also of her time in the center of a block of homes and a found more than expected in mixed forest (observed small business, and was often found in a nearby = 35.25%; expected = 28% of telemetry fixes), trailer park. whereas red foxes were found more than expected in In this study, red foxes were rarely found near pine forest (observed = 29.3%; expected = 24% of human habitations. One red fox was found behind a telemetry fixes) (Figure 6). Female foxes showed a housing complex on one occasion and the next day preference for fields and were found there more than was back inside the park. This is in contrast to other expected (observed = 51.4%; expected = 34% of published reports of red foxes. In England, red foxes telemetry fixes). Male foxes appeared to use mixed were often found in or near human habitations forest more than expected (observed = 35%, ex- (Harris 1981; Doncaster and Macdonald 1997). pected = 28% of telemetry fixes). The lone male gray Linzey (1998) reports that, the red fox occasionally fox in this study was found more than expected in wanders into urban habitats. the hardwood forest (observed = 66.75%; expected = Gray foxes and red foxes were found more than 28% of telemetry fixes), but was never found in the expected in fields. But red foxes used fields located mixed forest. Red fox males and gray fox females in the center of the park, whereas the fields used by preferred fields (observed = 43.9% and 58.7%; gray foxes were on the edge of the park. The core expected = 34% of telemetry fixes), whereas red fox area of one gray female was behind a convenience females preferred pine forest (observed = 35.2%; store and another was inside an urban block of expected = 24% of telemetry fixes). Only the gray houses and a small business. foxes were found in close proximity to human habitation (range 3.7% telemetry fixes for one gray

240 Proceedings 4th International Urban Wildlife Symposium. Shaw et al., Eds. 2004 Red foxes are believed to be recent immigrants to the southern peninsula. As late as 1948, the red fox Alderton, D. 1994. Foxes, wolves and wild dogs of was still scarce or absent on the southern peninsula the world. NY. Facts on file. 194 pp. (Linzey 1998). By contrast, gray foxes are indigenous Bueler, L. E. 1980. Wild dogs of the world. Stein and to this area (Linzey 1998). Red foxes moved onto the Day, New York. 274 pp. peninsula after urbanization was under way, but Burt, W. H. 1943. Territoriality and home range as gray foxes were here while these changes were applied to mammals. Journal of Mammalogy taking place. It is unclear how the immigration of the 24:346-352. red fox onto the southern peninsula affected the Dixon, K. R., and J. A. Chapman. 1980. Harmonic distribution of gray foxes. But continued loss of mean measure of animal activity areas. Ecology habitat is certain to affect the ranges and habitat 61:1040-1044. available to red foxes, gray foxes, and other carni- Doncaster, C. P., and D. W. Macdonald. 1997. Activ- vores. ity patterns and interactions of red foxes (Vulpes The City of Newport News and adjacent York vulpes) in city. The Journal of the Zoologi- County, which surround Newport News Park, are cal Society of 241:73-87. growing rapidly and new land will be needed to Environmental Systems Research Institute, Inc. 1996. build homes for this increasing human population. A ArcView GIS. Redlands, CA. new multi-family housing project is being built on Follmann, E. H. 1973. Comparative ecology and the south side of the park on land with mixed behavior of red and gray foxes. Doctoral Thesis, growth and a moderate-to-thick understory and a Southern Illinois University, IL. 153 pp. large field. One gray fox female heavily used both of Fritzell, E. K., and K. J. Haroldson. 1982. Urocyon these areas (91.5% of locations). The gray fox male in cinereoargenteus. Mammalian Species 189:1-8. this study and a red fox male not included in this Fuller, T. 1978. Variable home-range sizes of female analysis have also been found in this area. This land gray foxes. Journal of Mammalogy. 59:446-449. lies adjacent to the boundaries of the core study area. Hall, G. E., and D. A. Gaquin. 1997. 1997 County and It is unknown what effect the loss of habitat that city extra annual metro, city, and county data borders the park will have on the foxes and their book. Berana Press. MD. 1324pp. prey in the park, but development will certainly Harris, S. 1981. An estimation of the number of foxes decrease the area available for the current popula- (Vulpes vulpes) in the city of , and some tions and their future offspring. Another problem of possible factors affecting their distribution. Journal concern is how to keep these populations from of Applied Ecology 18:455-465. becoming genetically isolated. A corridor will need Harrison, R. L. 1995. The effect of rural residential to be maintained to allow foxes to move on and off development on the ecology and behavior of gray the peninsula. This will be a growing problem as foxes (Urocyon cinereoargenteus). M.S Thesis, Univ. more and more habitats become urbanized. of Albuquerque, NM. 133pp. Henry, J. D. 1996. Red fox: The catlike canine. ACKNOWLEDGMENTS Smithsonian Institution Press, Washington, DC. I would like to thank Dr. Harold N. Cones and Dr. 174 pp. Barbara A. Savitzky for their guidance and use of Hockman, J. G., and J. A. Chapman. 1983. Compara- their equipment. I wish to especially thank Michael tive feeding habits of red foxes (Vulpes vulpes) and D. Harrison for all his help in the field at all hours of gray foxes (Urocyon cinereoargenteus) in Maryland. the day and night and in all kinds of weather, and The American Midland Naturalist 110:276-285. Dr. Robert K. Rose for his guidance, use of his Jandel Scientific Software 1996. SigmaStat IIä for equipment, and for reviewing this manuscript. Windowsä. Jandel Scientific Software, San Rafael, CA. Linzey, D. W. 1998. The Mammals of Virginia. The REFERENCES MacDonald & Woodward Publishing Company, Ables, E. D. 1975. Ecology of the red fox in North Blacksburg, VA. 459pp. America. Pages 216-236 in M. W. Fox, ed. The wild Macdonald, D. W. 1987. Running with the fox. canids: their systematics, behavioral ecology and Unwin Hyman, London. 224pp. . Robert E. Krieger Publishing Co., Major, J. T., and J. A. Sherburne. 1987. Interspecific Malabar, Florida. relationships of coyotes, , and red foxes in Adkins, C. A., and P. Stott. 1998. Home ranges, western Maine. Journal of Wildlife Management movements and habitat associations of red foxes 51:606-616. (Vulpes vulpes) in suburban Toronto, Ontario, Mohr, C. O. 1947. Major fluctuations of some Illinois Canada. Journal of the Zoological Society of mammal populations. Proceedings of the Illinois London 244:335-346. Academy of Science 40:197-204.

Proceedings 4th International Urban Wildlife Symposium. Shaw et al., Eds. 2004 241 Nowak, R. N., and J. L. Paradiso. 1983. Walker’s Serow, W. J., and M. A. Spar. 1972. Virginia’s popula- th mammals of the world, 4 edition. The Johns tion: a decade of change. Graduate School of Hopkins University Press, Baltimore, MD. 1629pp. Business Administration. University of Virginia, Reynolds, J. C., and S. C. Trapper. 1995. The ecology Richmond, VA. of the red fox Vulpes vulpes in relation to small Sheldon, J. W. 1992. Wild dogs: the natural history of game in rural southern England. Wildlife Biology nondomestic Canidae. Academic Press, Inc., New 1:105-119. York. 239pp Samuel, M. D., D. J. Pierce, and E. O. Garton. 1985. Trapp, G. R., and D. L. Hallberg. 1975. Ecology of the Identifying areas of concentrated use within the gray fox (Urocyon cinereoargenteus): A review. Pages home range. Journal of Animal Ecology 54:711-719. 164-178 In M.W. Fox. ed. The Wild Canids: Their Sawyer, D. T., and T. T. Fendley. 1990. Seasonal home systematics, behavioral ecology and evolution. range size and movements behavior of the gray Robert E Krieger Publishing Co., Malabar, FL. fox on the Savannah River site, South Carolina. White, P. C. L., G. Saunders, and S. Harris. 1996. 1990 Proceedings annual conference of Southeast- Spatio-temporal patterns of home range use by ern Association of Fish and Wildlife Agencies foxes (Vulpes vulpes) in urban environments. 44:379-389. Journal of Animal Ecology 65:121-125.

242 Proceedings 4th International Urban Wildlife Symposium. Shaw et al., Eds. 2004 Table 1. Human Populations, Changes 1900 to 1990

Table 2. Home Ranges and Core Areas of Gray Foxes and Red Foxes in Newport News Park.

Proceedings 4th International Urban Wildlife Symposium. Shaw et al., Eds. 2004 243 Figure 1. Gray Foxes and Red Foxes Habitat Preferences.

244 Proceedings 4th International Urban Wildlife Symposium. Shaw et al., Eds. 2004